[54.06] A Relativistic Particle Model for LSI+61 303

D. Leahy (University of Calgary)

LSI+61o303 consists of a Be star in orbit with a compact
object, which has radio outbursts every 26.5 days. The radio
spectra are indicative of a self-absorbed synchrotron source
at the beginning of the outburst and optically-thin
synchrotron thereafter. LSI+61o303 is also an x-ray
source, which only recently was well characterized over a
full orbital period using RXTE/ASM observations (Leahy,
2001, A&A,380, 516). The x-ray light curve is well fit by
inverse compton of stellar photons by relativistic
electrons, which yields the epoch of periastron. The radio
outbursts occur near apastron, suggesting that the
relativistic electron population builds up around the
compact object until it expands and is released from the
binary system, resulting in a radio outburst.

Here will be reported the results of numerical modelling of
the injection and expansion of relativistic electrons, with
the effects of the Be stellar wind and of magnetic field
included. Due to the asymmetry imposed by the binary system
and stellar wind, a two dimensional calculation is required.
The results show that the relativistic fluid around the
compact object undergoes a relaxation oscillation, which
includes ejection, at the period of the binary system.

This work supported by the Natural Sciences and Engineering
Research Council of Canada.